JP4598635B2 - Component mounting equipment - Google Patents

Description

  The present invention relates to a component mounting apparatus, and more particularly to a component mounting apparatus suitable for application when electronic components are automatically mounted on a substrate such as a printed circuit board or a liquid crystal display panel substrate while applying pressure.

  As a component mounting apparatus that automatically mounts electronic components while applying pressure to a printed circuit board or the like, an apparatus including a mounting head shown in FIG.

  In the mounting head 100, the lowering operation at the time of component suction is performed as follows according to the flowchart of FIG.

  First, the initial load at the time of no load detected by the load cell 115 is stored (step 11), and can be moved along the linear guide 117 by the Z-axis motor (first vertical movement means) 121 according to the control of the operation control means (not shown). The bracket 114 is driven downward toward the lowering target position (step 12).

  At this time, the voice coil motor (second up-and-down moving means) 134 drives the lower flange 135 downward until it comes into pressure contact with the thrust bearing 136 according to the control of the operation control means (step 13). Prevent vertical vibration.

  During the lowering operation of the movable bracket 114, the operation control means determines whether or not the detected value of the applied pressure based on the output of the load cell 115 exceeds the total value of the initial load and the lowering threshold value (step 14). In this case, it is determined from the output of the encoder 122 whether or not the lowering target position has been reached (step 15). If not, the process returns to step 14 again.

  On the other hand, when the tip of the suction nozzle 112 comes into contact with the electronic component C due to the lowering of the movable bracket 114, the detected pressure of the load cell 115 increases and exceeds the total value of the initial load and the threshold value during pressurization. As a result, the operation control means performs operation control to drive the voice coil motor 134 upward (step 17), and returns to step 14. The operation control means compares the detected pressure of the load cell 115 with the total value of the initial load and the lowering threshold value, and when the detected pressure is higher, the voice coil motor 134 further controls to drive the rotating case 131 upward ( Step 17).

  If the detected pressure is lower (NO) in step 14, the process proceeds to step 15, and the current position of the movable bracket 114 is confirmed from the output of the encoder 122.

  If it is determined that the movable bracket 114 has reached the lowering target position (YES in step 15), the operation control means stops driving the Z-axis motor 121 (step 16). Thereby, the lowering operation control of the suction nozzle 112 is completed. After the descent operation, the tip of the suction nozzle 112 is in contact with the electronic component C with a target pressure, and the control means starts driving a negative pressure supply means (not shown). Operation control is performed, and the suction of the electronic component C is performed at the tip with the suction nozzle 112 having a negative pressure.

  As described above, when the suction of the electronic component C is completed, the Z-axis motor 121 is driven, the bracket 114 is raised and the suction nozzle 112 is lifted, and then the mounting head 100 is moved above the substrate. In accordance with the same procedure, the mounting control for mounting the component at the target position on the board under the target pressing force is performed.

JP 2004-158743 A

  However, the electronic component mounting apparatus disclosed in Patent Document 1 has the following problems.

(1) The problem that a collision load is generated when the nozzle comes into contact When the movable bracket 114 is lowered, the voice coil motor 134 presses the lower flange 135 against the thrust bearing 136 to prevent vertical vibration. For this reason, when the suction nozzle 112 is in contact with a component or when it is in contact with the substrate while the component is being sucked, an excessive pressing force pressing against the thrust bearing 136 is applied to the component.

(2) The problem that the suction nozzle 112 moves away from the component during the pressure lowering operation After the front end portion of the suction nozzle 112 contacts the electronic component C, operation control is performed to drive the voice coil motor 134 upward. If the raising speed of the suction nozzle 112 by the voice coil motor 134 is too fast than the lowering speed at which the movable bracket 114 is driven downward by the motor 121 toward the lowering target position, the suction nozzle 112 may be separated from the component. Also, in the case of component mounting, it may be separated from the substrate, and as a result, component adsorption errors and mounting errors occur.

  The present invention was made to solve the above-described conventional problems, and prevents an excessive collision load from being generated from the nozzle to the component when the component is adsorbed by the adsorption nozzle or when the substrate of the adsorption component is mounted. It is an object of the present invention to provide a component mounting apparatus that can reliably suck and mount components.

  The present invention includes a suction head that sucks and holds a component by a mounting head that can be moved in a plane direction by an X-axis drive means and a Y-axis drive means, and a pressure drive means that moves the suction nozzle back and forth in the Z-axis direction, In a component mounting apparatus including a Z-axis driving unit that moves the suction nozzle forward and backward in the Z-axis direction integrally with the pressure driving unit, the suction nozzle is lowered by the Z-axis driving unit, and the nozzle is moved to the surface of the component. Or when the component adsorbed to the nozzle is brought into contact with the substrate surface, before contact, the suction nozzle is moved by the pressure driving means at a speed whose absolute value is smaller than the descending speed by the Z-axis driving means. By providing a control means for performing control to raise, the above-mentioned problem is solved.

  In the present invention, after the contact, the suction nozzle is lowered by the pressure driving means at a speed whose absolute value is larger than the lowering speed by the Z-axis driving means, and pressurization control is performed until a target pressurization amount is reached. May be performed.

  According to the present invention, immediately before the suction nozzle comes into contact with the component surface or the suction component comes into contact with the substrate surface, the lowering speed of the nozzle by the Z-axis driving means is reduced by the raising operation by the pressure driving means. Therefore, the impact force when the suction nozzle (or component) comes into contact with the surface of the component (or substrate) can be alleviated, and the suction or mounting can be performed with reliable contact.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of an electronic component mounting apparatus according to an embodiment of the present invention.

  In FIG. 1, the mounting head 1 includes a pressurizing device that sucks and holds parts and pressurizes, and a recognition device (not shown) that corrects the position of the mounting head 1.

  The mounting head 1 is attached to an X-axis gantry (X-axis drive means) 2 that moves the electronic component mounting apparatus in the X-axis direction. The mounting head 1 and the X axis gantry 2 are attached to a Y axis gantry (Y axis driving means) 3 for moving in the Y axis direction of the electronic component mounting apparatus.

  Further, in this electronic component mounting apparatus, a recognition device 4 using a CMOS camera or a CCD camera for recognizing the posture of the sucked electronic component is fixed within the movable range of the mounting head 1. An electronic component supply device 5 for supplying an electronic component to be mounted on a substrate is installed on the front surface of the electronic component mounting device.

  Next, the mounting head 1 will be described with reference to FIGS.

  The mounting head 1 has a head base 6 for connecting and fixing to the X-axis gantry 2. The head base 6 is connected to the linear guide 7, and the vertical Z-axis drive unit 15 is configured to be movable in the vertical Z-axis direction.

  Above the head base 6 is a vertical rotation drive bearing 21 and a vertical rotation drive shaft 22 composed of a θ motor 9 for rotating parts, a spline bearing and a bearing, and the power of the θ motor is rotated vertically. A Z-axis motor (Z-axis drive means) 11 for vertically moving the belt 10 and the vertical Z drive unit 15 transmitted to the drive shaft 22 is attached. Further, a threaded portion 14 of a ball screw is connected to the Z-axis motor 11 via a coupling 12.

  A voice coil motor for pressurization (pressurization drive means, hereinafter referred to as VCM) 8 is attached to the upper part of the vertical Z drive unit 15. The VCM 8 is connected to the θ motor 9 via a vertical rotation drive shaft 22, and the drive side 8 b of the VCM 8 is supported independently of the vertical Z drive unit 15 by the vertical rotation drive shaft 22. Therefore, the vertical Z driving unit 15 can be rotated and moved up and down.

  A ball screw nut portion 13 is fixed to the vertical Z drive portion 15, and a ball screw screw portion 14 connected to the nut portion 13 via the coupling 12 is fitted into the nut portion 13. The Z-axis motor 11 is rotated and the vertical Z drive unit 15 can be moved up and down by the nut portion 13 of the ball screw.

  Further, a cylindrical pressure detection unit 16 is built in the vertical Z drive unit 15, and the pressure detection unit 16 is a ball between the outer periphery and the inner periphery of the vertical Z drive unit 15. Via the guide bearing 17, the vertical Z driving unit 15 can be rotated and vertically moved up and down.

  A nozzle shaft 18 extends downward at the lower portion of the pressure detection unit 16, and a suction nozzle 20 is held by a nozzle chuck mechanism 19 at the lower end of the nozzle shaft 18 and has a replaceable structure. It has become. The nozzle 20 can suck and hold a component (not shown) and mount the component on a substrate (not shown).

  Next, the pressure detection unit 16 and the like will be described with reference to FIG.

  The VCM 8 is attached to the upper portion of the pressure detection unit 16, and a coil (not shown) is wound around the fixed side 8 a that is an outer cylinder of the VCM 8 with the vertical Z drive unit 15. Further, a magnet is attached to the drive side 8b of the VCM 8, and the VCM 8 can be linearly driven in the vertical direction by energizing the coil on the fixed side 8a of the VCM 8. The shaft 22 is extended at the center of the drive side 8 b of the VCM 8 and is coupled to the upper portion of the pressure detection unit 16.

  An upper stopper 23a and a lower stopper 23b using thrust bearings are attached to the upper and lower sides of the shaft fixed to the drive side 8b of the VCM 8. The upper stopper 23 a comes into contact with the lower part 6 a of the head base 6, and the lower stopper 23 b comes into contact with the upper part 15 a of the vertical Z drive unit 15.

  That is, the vertical movement amount of the VCM 8 is regulated by the upper stopper 23a and the lower stopper 23b. However, even when the movement amount of the VCM 8 is restricted by contacting the upper stopper 23a or the lower stopper 23b, the thrust side is used, so that the drive side 8b can be rotated.

  The internal structure of the pressure detection unit 16 will be described. The load cell 24 is fixed downward on the upper portion thereof. An upper support plate 25a for receiving a spring is attached below the load cell 24. A pressurizing spring 26 is provided below the upper support plate 25a, and a lower support plate 25b for receiving a lower portion of the pressurizing spring 26 is attached below the pressurizing spring 26.

  The nozzle shaft 18 is fixed to the lower side of the lower support plate 25b, and the nozzle shaft 18 has a structure capable of moving up and down by a spline bearing 28.

  A step portion 16a is provided below the lower support plate 25b in the pressure detection unit 16, and is smaller than the outer shape of the lower support plate 25b so that the lower support plate 25b abuts.

  A self-weight canceling spring 27 is attached below the lower support plate 25b between the spline bearing 28 and pushes up the lower support plate 25b. The spring force of the self-weight canceling spring 27 supports the spring force of the pressurizing spring 26, the weight of the lower support plate 25b, and the combined weight of the nozzle shaft 18, the nozzle chuck mechanism 19 and the nozzle 20. .

  In addition, the spring force of the self-weight canceling spring 27 is set slightly lower than the force supporting these, and the lower support plate 25b is configured to abut against the stepped portion 16a in the no-load state. Accordingly, the lower support plate 25b is normally pressed against the step portion 16a with a weak force, and when a load greater than the weak force is applied to the nozzle 20, the load cell 24 detects it.

  In the above configuration, an electronic component suction operation and a pressure mounting operation performed by a control device (not shown) will be described with reference to FIGS. 4, 5, and 6.

  The mounting head 1 shown in FIG. 1 is moved above the electronic component supply device 5 by driving the X-axis gantry 2 and the Y-axis gantry 3, and the electronic components are sucked by the suction nozzle 20.

  The mounting head 1 that has attracted the electronic component is moved above the recognition device 4, and the recognition device 4 recognizes the component.

  After completing the recognition of the components, the mounting head 1 is moved to a mounting portion of an electronic component on a substrate (not shown), and the electronic component sucked by the suction nozzle 20 of the mounting head 1 is mounted on the mounting position on the substrate. To do.

  Hereinafter, these operations will be described in detail. In the component suction operation, the mounting head 1 is driven at the component suction position on the component suction device 5 by driving the Z-axis motor 11 and lowering the suction nozzle 20 together with the vertical Z drive unit 15.

  At that time, a voltage is applied to the VCM 8 to generate a downward force, and the lower stopper 23b is abutted against the upper portion 15a of the vertical Z drive unit 15 as shown in FIG. 4 to regulate the downward movement of the VCM 8. deep.

  The suction nozzle 20 is lowered by the Z-axis motor 11, and the suction nozzle 20 is rapidly stopped at a height immediately before the suction surface of the part to be sucked. At this time, although the inertial force works downward due to the weight of the pressure detection unit 16 and the acceleration at the time of deceleration, the position is regulated by the lower stopper 23b of the VCM8, so that it exceeds the force generated by the VCM8. Even if the inertial force is exerted downward, no change is observed in the position of the nozzle tip.

  Further, since the lower support plate 25b of the pressurizing spring 26 abuts against the step 16a inside the pressurization detection unit 16 and is positioned, the nozzle shaft 18 is connected to the nozzle shaft 18 by the inertial force due to acceleration during deceleration. The lower support plate 25b is prevented from being pushed down.

  After the suction nozzle 20 is rapidly stopped, the Z-axis motor 11 is operated slowly to suppress the collision load, and the pressurizing operation for applying the specified load pressure to the component is performed by the pressurizing VCM 8 while the component is sucked and held. The pressurizing operation at the time of component adsorption is basically the same as that at the time of component mounting, which will be described later, except for the applied load pressure, and the description thereof is omitted.

  After attracting and holding the component, the Z-axis motor 11 is driven to raise the component, and the mounting head 1 is moved to move onto the recognition device 4.

  A recognition operation for component position correction is performed, and then the component is moved to the mounting position (above the board), and the following component mounting operation is performed.

  The descending / pressurizing operation when mounting the components will be described with reference to the time chart shown in FIG. The descending operation at the time of component mounting is basically the same as that at the time of component adsorption described above except that the component is adsorbed by the nozzle 20.

  When the Z-axis motor 11 is driven, the lower stopper 23b is in the state shown in FIG. The first position Z1 is lowered at a high speed (time T1). Next, the speed is switched, and the movement is started at a low speed to the second position Z2 set below the height (= 0) of the upper surface of the substrate (time T2). The Z-axis height such as Z1 is determined by the encoder output built in the Z-axis motor 11.

  When a control device (not shown) receives a signal from the encoder that the movement to the first position Z1 at which the component does not contact the upper surface of the board by the Z-axis motor 11 is received from the encoder, the VCM 8 is energized, and the drive side 8b of the VCM 8 Then, the pressure detection unit 16 that moves up and down connected thereto, the nozzle shaft 18, the nozzle chuck 19, the suction nozzle 20, the stoppers 23a and 23b, and the like generates a pressing force of the weight + α of the movable unit to move upward. Part self weight cancellation + α force V1 is generated. As a result, the lower stopper 23b changes from the state of FIG. 4 to the unregulated state of FIG.

  The suction nozzle 20 descends as it is, and at time T0, the suction nozzle 20 reaches the height 0 of the upper surface of the substrate, and the nozzle 20 (component) contacts the substrate.

  During the time T2, the relationship between the lowering speed Vz of the nozzle 20 by the Z-axis motor 11 until contact (before contact) and the upward movement speed Vv due to the self-weight cancellation of the movable part + α by the VCM 8 is shown in FIG. As shown in the table, the speed is set so that Vz> Vv.

  Thus, by lowering the moving speed Vv upward by the VCM 8 from the descending speed Vz by the Z-axis motor 11 of the nozzle 20 (decreasing the absolute value in the reverse direction), the position of the nozzle 20 by the encoder output is the second. Before reaching the position Z2, as shown in FIG. 5, it is possible to prevent the VCM 8 from being out of control due to the operation up to the stroke end of the VCM 8 and the upper stopper 23a colliding with the lower portion 6a of the head base.

  Further, when the upper stopper 23a collides with the lower portion 6a of the head base in this way, the nozzle 20 is not in contact with the substrate even after the position of the nozzle 20 by the encoder output reaches the second position Z2. Although it is possible that parts cannot be mounted, it is possible to prevent such a situation from occurring.

  At time T2, even if the nozzle 20 contacts the substrate at time T0, the Z-axis motor 11 does not stop driving until the encoder output becomes Z2. This Z2 is set to a height at which the nozzle 20 (component) is sufficiently in contact even when the VCM 8 raises the movable portion with the output of V1 and the state shown in FIG.

  On the other hand, when the VCM 8 receives the contact signal of the nozzle 20 from the load cell 24, the VCM 8 switches to a downward force and gradually pressurizes the pressurization amount to the target pressurization amount of the set output value V2. When the target pressurization amount is reached, pressurization is stopped, the target pressurization amount is held for a preset pressurization time T3, the pressurization operation is terminated, and the Z-axis motor 11 After raising the nozzle 20, that is, the vertical Z drive unit 15, the XY movement of the mounting head 1 is performed.

  Further, the relationship between the lowering speed Vz of the nozzle 20 by the Z-axis motor 11 after contacting the substrate at time T0 at time T2 and the downward moving speed Vv due to the applied pressure of the VCM 8 is shown in FIG. As shown, the speed is set so that Vz <Vv.

  Thus, by making the moving speed Vv downward by the VCM 8 higher than the lowering speed Vz by the Z-axis motor 11 of the nozzle 20 (increase the absolute value in the same direction), pressurization giving priority to the lowering action by the VCM 8. Control becomes possible, and it is possible to perform control in which the operation of the Z-axis is considered (considered) as a disturbance, so that highly accurate control can be performed.

  Next, the component mounting operation conceptually described above will be described more specifically with reference to FIGS.

  Lowering is performed at a high speed Vz to a first position Z1 that is at a height that does not contact the upper surface of the substrate and is slightly displaced from the upper surface (time T1).

The distance by the encoder output from the position of the height Z1 before the substrate contact to the position of the second height Z2, which is the height below the substrate, is 0.6 mm (Z1 to Z2: 0.6 mm). Further, the movable stroke Z _VST of the VCM is set to 3 mm.

  The distance between Z1 and Z2 is a sufficient height of 0.1 mm that does not contact the substrate, a displacement amount of 0.2 mm that the substrate bends when the VCM pressurizes the components, and a margin of variation of the substrate height of 0.3 mm. The distance is set in consideration of

  For example, the operating conditions of the lowering speed Vz by the Z-axis motor and the moving speed Vv by the VCM are set as follows. The direction is positive (+) for downward and negative (-) for upward.

Vz = 10mm / sec (downward)
VCM speed V _VB before substrate contact = -6.7 mm / sec (upward)
VCM speed V _VA after substrate contact = 20 mm / sec (downward)

[Z1-0 (substrate contact): T _2B ]
The Z-axis motor starts to descend toward the height of Z2 at Vz = 10 mm / sec.

Simultaneously with the start of the lowering of the Z-axis motor, a voltage is applied so that the VCM moves upward at a speed V _VB = −6.7 mm / sec.

If the time until contact is T _{2B at} this time, the relational expression is
(Z1 + Zv) = Vz × T _2B , Zv = V _VB × T _2B (1)
It becomes.

  Assuming that the distance Z1 is 0.1 mm, the amount of increase in VCM at that time is calculated as follows by substituting Z1 = 0.1 mm into the relational expression (1).

    Zv = 0.2mm

This value is sufficiently small for the VCM stroke Z _VST = 3 mm, so that the upper stopper 23a does not collide (see FIG. 9).

[0 (substrate contact) _{~Z2: T 2A]}
The Z-axis motor continues to descend toward the height of Z2 at Vz = 10 mm / sec.

After contact with the substrate, the VCM speed is changed to V _VA = 20 mm / sec and pressurization is performed. At this time, the speed of the VCM is sufficiently higher than the speed of the Z-axis motor. Therefore, in the pressing operation by the VCM, the control considering the Z-axis operation as a disturbance can be performed, and high-precision control is performed. Can do.

  According to the embodiment described above, the following effects can be obtained.

  (1) Since an upward force is generated in the nozzle before the suction nozzle 20 (component) mounted on the mounting head 1 comes into contact with the component (substrate), the impact load can be reduced.

  (2) Before the suction nozzle 20 (component) comes into contact with the component (substrate), the moving speed Vv upward by the VCM 8 is made slower than the descending speed Vz by the Z-axis motor 11, so that the nozzle 20 Before reaching the position, the VCM 8 moves to the stroke end and the upper stopper 23a collides with the head base portion 6a to prevent the VCM 8 from being uncontrollable (a state in which pressurization is not possible because the nozzle does not contact the substrate). can do.

  (3) After the nozzle (component) contacts the component (board), the movement speed Vv of the nozzle by the VCM 8 is made faster than the descending velocity Vz of the nozzle by the Z-axis motor 11, thereby operating the Z-axis motor. It is possible to perform control considering the disturbance, and it is possible to perform highly accurate control.

  (4) By changing the control method (drive voltage level) of the VCM 8 before and after the suction nozzle (component) contacts the component (substrate), the above-described malfunction of the mounting head 1 can be prevented, and the weight of the movable part including the nozzle can be reduced. Stable load control is possible even in a minute load range smaller than the above.

  Although the present invention has been specifically described above, the present invention is not limited to that shown in the embodiment.

  For example, the pressure driving means may not be a VCM but an air cylinder or the like, and is not particularly limited as long as the structure can operate in the vertical direction.

  Further, although one load cell is used as the load detector, other load cells may be used, and two or more load cells may be used, depending on the detected pressurization amount.

  Further, although the spring is used for pressurizing the load cell and canceling the self-weight of the pressurization detecting unit, it may be other than the spring as long as it is an elastic body. Further, depending on the application (when the vibration of the nozzle is not so much a problem, or when the weight of the nozzle changes due to the replacement of the nozzle, etc.), the structure may be such that the self-weight cancel spring / pressurizing spring can be easily replaced. Or it is good also as a structure which can attach or detach the step part 16a as a cyclic | annular spacer.

  Further, the lowering speed of the nozzle by the Z-axis motor: the moving speed by Vz or VCM (control voltage level): Vv may be changed according to the component type (according to the required pressurizing amount). These parameters may be set in the control device in advance for each component type and automatically changed.

  For example, in the case of a part where the amount of pressure applied when the part is pressed is large and the impact load does not matter so much, the nozzle lowering speed should be fast enough to prevent the collision load from destroying the part and be mounted as fast as possible. On the other hand, in the case of a fragile part, the nozzle lowering speed may be changed by making the nozzle lowering speed very slow to reduce the collision load.

  Further, when mounting a component while pressing the component against the substrate, if the substrate on which the component is mounted is easily bent, a moving amount of the pressing operation of the VCM after contacting the substrate is required. In that case, by setting the moving speed upward by the VCM before contact within a range that does not exceed the descending speed of the nozzle, the amount of increase until the nozzle contacts the substrate is increased, and the pressure after the substrate contact You may make it ensure the stroke of time.

1 is a schematic perspective view schematically showing a component mounting apparatus according to an embodiment of the present invention. Side view including a cross section showing a mounting head provided in the component mounting apparatus of the present embodiment Partial sectional view centering on the movable part by VCM of the mounting head. Partial sectional view showing the movable part in the descending restricted state Partial sectional view showing the movable part in the ascending regulation state Time chart showing the outline of pressurizing operation when mounting components according to this embodiment Chart showing the relationship between the speed by the Z-axis motor and the speed by the VCM before and after contacting the substrate of the suction nozzle Time chart showing details of pressurizing operation when mounting components according to this embodiment Explanatory drawing which shows the relationship between the movable part before the substrate contact of the nozzle (component) and the substrate contact Sectional view showing the outline of a conventional mounting head Flow chart showing component mounting operation by conventional mounting head

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Mount head 2 ... X-axis gantry 3 ... Y-axis gantry 8 ... Voice coil motor (VCM)
DESCRIPTION OF SYMBOLS 11 ... Z-axis motor 15 ... Vertical Z drive part 16 ... Pressure detection part 20 ... Adsorption nozzle 24 ... Load cell

Claims (2)

A mounting head that is movable in the plane direction by the X-axis driving means and the Y-axis driving means has a suction nozzle that sucks and holds components, a pressure driving means that moves the suction nozzle back and forth in the Z-axis direction, and the pressure driving In a component mounting apparatus comprising a Z-axis driving means for moving the suction nozzle back and forth in the Z-axis direction integrally with the means,
When lowering the suction nozzle by the Z-axis driving means and bringing the nozzle into contact with the component surface, or when bringing the component sucked into the nozzle into contact with the substrate surface,
A component mounting apparatus comprising control means for controlling the suction nozzle to be lifted by the pressure driving means at a speed whose absolute value is smaller than the descending speed by the Z-axis driving means before contact.   After the contact, the suction nozzle is lowered by the pressure driving means at a speed whose absolute value is larger than the lowering speed by the Z-axis driving means, and pressure control is performed until a target pressurizing amount is reached. The component mounting apparatus according to claim 1.

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